Conventionally, laser processing apparatuses that irradiate a laser onto a workpiece to process the workpiece have been widely utilized. For example, there is a laser processing apparatus that has a workpiece conveying unit that conveys a workpiece and a laser-beam scanning unit that performs laser beam scanning. According to this laser processing apparatus, when a laser beam is scanned onto a workpiece by the laser-beam scanning unit while the workpiece is moved by the workpiece conveying unit at a constant rate in a certain direction to process the workpiece, an angle created by a laser-beam scanning direction and a conveying direction is changed according to a rate at which the workpiece is conveyed, so that a laser processing is performed linearly in a direction orthogonal to the conveying direction regardless of the rate at which the workpiece is conveyed (see, for example, Patent Literature 1).